The present invention relates to immersion wells used in boilers, hot water heaters and other fluid vessels. It more particularly relates to such immersion wells which house mechanical temperature sensors. It further relates to constructions of electronic temperature sensing and computer control or display systems for hot (or cold) fluid vessels.
It is often desirable to further control or automate an existing boiler or hot water system to make it more efficient and thus less expensive to run. Some type of (usually mechanical) temperature sensor is already provided on these vessels to control the burners when the temperature of the fluid in the vessel reaches a predetermined temperature. These systems typically are simple on/off systems and turn the burner on and off when the water reaches certain temperatures. There are three common ways of attaching the electronic sensor to an existing vessel to obtain a temperature indication for the control equipment to make the system more efficient.
One method is to burn a hole into the tank, weld a fitting at the hole, and thread the sensor housing into the fitting. As an example, a welder takes a Weld-o-let, which is a piece of metal or steel with a threaded interior, places it on top of the opening and then welds around it making an effective attachment and seal. This procedure is rather time-consuming and expensive, however, and requires special welding skills and workman certifications.
Another method is to strap a sensor onto a piping or other portion of the fluid system. Often the pipe is insulated so the insulation must first be removed according to this method, the exposed surface of the pipe cleaned, a heat transmitting paste applied thereon, the sensor stuck in the paste a strap placed around the entire pipe circumference clamping the sensor down and the insulation then replaced. It is thus the temperature of the surface of the pipe which is then sensed and not necessarily that of the fluid in the pipe. This surface temperature can not only differ from but also lag that of the fluid inside of the pipe at that location. Another disadvantage is that often the strapped-on sensor often is not and cannot be placed at the preferred location on the vessel near the strata of fluid whose temperature is preferably to be determined.
A third method of applying the electronic temperature sensor to an existing vessel is to insert it into an unused preexisting tapping. These tappings usually are not present, however, and when they are, they are often corroded shut.